Rat linked to Fukushima outage

A spokesman for Tokyo Electric Power Co. (TEPCO) said that a 15-centimeter (6-inch) rat was found dead on Wednesday near a switchboard.

While the company said it had its suspicions that the rat was linked to the power failure, it said that further investigation was required.

The failure prevented the operation of cooling equipment serving four pools where spent fuel was being stored, prompting fears that the temperature could rise to a critical meltdown level.

"We suspect a small animal may have caused a short circuit in a switchboard" the spokesman said. “We cannot be sure exactly what it was, but can say what we saw at the scene was the body of a dead animal below the switchboard."

"In our investigation we will concentrate on getting assurances that it was definitely this animal that caused the short circuit," the spokesman added.

A temporary arrangement

The switchboard is reported to have been housed in the back of a truck parked outside the facility - a temporary arrangement that TEPCO said it had been planning to fix. The company released a photograph that appeared to show the body of a rat.

Cooling systems serving four storage pools at the plant were knocked out on Monday but came back on line early Wednesday morning. Used nuclear fuel can become dangerous when its temperature rises to a point at which a self-sustaining critical reaction begins, leading to a meltdown.

Nine facilities in all were affected by the power cut, although TEPCO said that the cooling of the reactors themselves was never in jeopardy. Company officials say there has been no major change to the level of radioactivity at nearby monitoring spots.

The meltdown of three out of six reactors at Fukushima followed an earthquake and subsequent tsunami wave in March 2011, which shut off power to cooling systems serving the reactors.

rc/dr (AFP, AP, dpa)